1. Field of the Invention
The present invention concerns a press for foods such as ice, fruit and vegetables.
2. Related Art
Presses for fruit and vegetables are known in the art. The "cone" type machines incorporate a fixed or mobile conical member over which the previously halved fruit is placed. The pressure applied to the fruit combined with rotation of the fruit or of the cone extracts the juice from the fruit. These machines are operated semi-automatically or automatically, the cone being rotated, or manually.
Although their operation is generally satisfactory, these machines have a number of inadequacies that the invention proposes to alleviate. These cone-type machines are limited to certain types of fruit, to be more precise they are limited to citrus fruit. What is more, where a relatively high throughput is required these machines are limited to a single type of citrus fruit (oranges or grapefruit, for example), and furthermore the fruit used must be of a certain size, and this increases the cost of the fruit juice. Nor is the throughput of these machines satisfactory, especially given that the demand for freshly squeezed fruit is on the increase and that large quantities, for example several hundred liters per hour, may be required from the press, for example in a large hotel at breakfast time.
Also known are centrifuge type machines in which pieces of fruit are centrifuged to extract the juice. These machines are characterised by a high noise level and a high price. As is also known, the quality of the fruit juice obtained is not so good because the centrifuged fruit juice is generally emulsioned, which spoils the taste. The construction of the machine is also somewhat complicated and as it must be cleaned relatively frequently, which is a time-consuming operation, the result is a relative loss in yield.
The present invention is directed to a press that is designed to enable fruit to be pressed with a high throughput, that is simple to use, that yields juice with a quality at least as good as cone-type machines, that is low in cost and that is suitable for private use as well as in large scale catering operations and drinks outlets.
The present invention is also directed to a press of significantly simpler construction than those briefly described above and which is much easier to use, especially in a bar or in a restaurant, and which offers a higher throughput than the prior art machines.
To this end the present invention is directed to a food press of the kind comprising pressing means adapted to operate on the food(s) to be pressed comprising at least one grid and at least one plate between which the food(s) must be placed, characterised in that hydraulic operating means are associated with said pressing means and adapted to move the grid and the plate towards each other so that they exert pressure on the food(s), the hydraulic operating means comprising at least one single-acting piston-and-cylinder actuator operated by a hydraulic pump adapted to operate in compression and in suction.
By virtue of these arrangements the food(s) are not centrifuged in the press and consequently the juice is not emulsioned and retains its natural taste. The cone of cone-type machines is dispensed with, enabling the machine in accordance with the invention to be used not only with citrus fruits but also with all sorts of fruits and vegetables, such as pineapples or tomatoes, for example.
It will therefore be noted that the machine in accordance with the invention can be used to press pineapples, the juice from this fruit being usually obtained in the prior art only by means of centrifuges so that it cannot be obtained by private persons or restaurateurs who do not own a centrifuge. What is more, the pressure required to press this kind of fruit is relatively high, which can only be achieved with difficulty in the prior art but which is rendered possible by the combination of means in accordance with the invention.
Similarly, the machine in accordance with the present invention can be used to crush ice, which is not so in the prior art presses described above, for the same reasons among others.
Another advantage of dispensing with the cone lies in the fact that the pulp is not torn out from the fruit but is rather crushed. As a result of this feature there is no need to clean the grid frequently whereas in a cone-type machine the detached pulp quickly blocks the filter associated with the machine.
The means employed are particularly simple since the hydraulic operating means essentially comprise one or more single-acting piston-and-cylinder actuators associated with a simple design pump.
These hydraulic means produce a high pressure for a low consumption of energy which not only improves the quality with which the fruit is pressed but also reduces the energy cost of the pressing operation. What is more, pressing can be carried out much more quickly with the device in accordance with the invention as the positioning of a fruit on a cone is avoided. With the press in accordance with the present invention it is sufficient to cut the fruit into two parts and to place the latter between the plate and the grid. The fruit pressing yield and throughput are thus increased, which is particularly benefical.
Note that the hydraulic means employed are particularly simple to implement and therefore relatively inexpensive.
The invention uses only one or more single-acting piston-and-cylinder actuators associated with a hydraulic pump able to operate in compression and in suction.
By virtue of these arrangements, when the pressing is completed the pump is reversed and the actuator returns to its idle position as a result of suction.
In a preferred embodiment this return movement is advantageously accelerated by a spring. This further increases the throughput of the press since it is ready to receive further foods within a few seconds of pressing the previous foods, the plate returning quickly to the open position.
In this preferred embodiment a pressure sensor is included in the hydraulic circuit and is associated with means for reversing the pump drive motor when a pressure threshold is reached.
These arrangements ensure that the press in accordance with the invention is safe to use and further facilitate its use since the machine is entirely automated. What is more, by choosing a sufficiently high pressure threshold particularly strong foods such as pineapples or ice can be pressed efficiently before the machine returns to the rest position.
The pump used is of simple construction since it operates in suction in the reverse direction: there is therefore no need in this case to provide means to enable the pump to operate in compression in both directions. In this way the present invention economises on a hydraulic pump operating in compression in both directions, double-acting actuators and a distributor.
It will likewise be noted that the machine in accordance with the present invention is particularly quiet in operation, which is not the case with prior art machines, centrifuges in particular.
In the preferred embodiment the grid is fixed and the plate is mobile.
To use the press it is therefore sufficient to place the foods on the grid, against which they are pressed by the plate. These arrangements are particularly simple and inexpensive to implement.
In this embodiment the plate is mounted on a first arm of at least one lever, the fulcrum of the latter being mounted to pivot about an axis, while the hydraulic means operate on the second arm of the lever.
By virtue of this arrangement it is possible in the known way to multiply the force of the hydraulic means and so to increase the pressure with minimum energy consumption.
The characteristics and advantages of the presention invention will emerge from the following description given with reference to the appended drawings in which: